High power transmitter employing a high power QAM modulator

Abstract

A high power RF transmitter that uses high power modulators that perform quadrature amplitude modulation (QAM) on a carrier signal after power amplification that is performed in the RF carrier source. The present invention transposes the locations of the modulators and power amplifier, and thus directly modulates a high power carrier signal. An RF carrier source generates a high power RF carrier signal that is split by a power splitter. A lookup table containing 2 B words by K bits receives transmit data and mapping data and generates K-tuple modulating data. A plurality of phase key modulators are respectively coupled to outputs of the power splitter and to the lookup table and phase key modulate each of the signal components of the carrier signal using the K-tuple modulating data. A power combiner is coupled to outputs of the phase key modulators for outputting a high power QAM constellation from the transmitter.

What is claimed is: 
     
       1. A high power transmitter comprising: a high power RF carrier source for generating a high power RF carrier signal;   a multiple output power splitter coupled to the high power RF carrier source;   a lookup table containing 2 B  words by K bits for receiving n-tuple transmit data that is to be transmitted and mapping data that maps the transmit data to the stored words in the lookup table, for generating K-tuple modulating data;   a plurality of phase key modulators that are respectively coupled to each of the outputs of the power splitter and to the lookup table for phase key modulating each of the signal components of the carrier signal using the K-tuple modulating data supplied by the lookup table; and   a multiple input power combiner coupled to outputs of the phase key modulators for outputting a high power QAM constellation from the transmitter.   
     
     
       2. The transmitter of claim 1 wherein the plurality of phase key modulators each comprise binary phase shift keying modulators. 
     
     
       3. The transmitter of claim 2 wherein the plurality of phase key modulators each comprise quadrature phase shift keying modulators. 
     
     
       4. The transmitter of claim 1 wherein 6-tuple transmit data is supplied to the lookup table which contains 64 words by 14 bits, the lookup table outputs 14-tuple modulating data that are supplied to the modulators, the power splitter comprises a seven way power splitter whose outputs are coupled to seven QPSK modulators, and the power combiner comprises a seven way power combiner that combines the outputs of each of the modulators to produce a 64 QAM constellation that is output from the transmitter. 
     
     
       5. The transmitter of claim 1 further comprising: a 90° hybrid 1 for splitting the carrier signal along two paths;   and wherein the power splitter comprises two seven way power splitters respectively disposed along the two paths that separately distribute the split carrier signal;   and wherein the split carrier signals are coupled by the two seven way power splitters to first inputs of two sets of seven bi-phase modulators;   and wherein the lookup table contains 64 words by 14 bits, and whose output is 14-tuple modulating data that are supplied to respective second inputs of the bi-phase modulators;   and wherein the power combiner comprises two seven way power combiners that combine the outputs of the respective sets of modulators;   and wherein the transmitter further comprises a 0° hybrid coupled to the seven way power combiners for combining the respective outputs thereof to produce a 64 QAM constellation that is output from the transmitter.   
     
     
       6. A high power transmitter comprising: a high power RF carrier source for generating a high power RF carrier signal;   a seven way power splitter coupled to the high power RF carrier source;   a lookup table containing 64 words by 14 bits for receiving 6-tuple transmit data that is to be transmitted and mapping data that maps the transmit data to the stored words in the lookup table, for generating 14-tuple modulating data;   a plurality of phase key modulators that are respectively coupled to each of the outputs of the power splitter and to the lookup table for phase key modulating each of the signal components of the carrier signal using the K-tuple modulating data supplied by the lookup table; and   a seven way power combiner coupled to outputs of the phase key modulators for outputting a high power 64 QAM constellation from the transmitter.   
     
     
       7. The transmitter of claim 6 wherein the plurality of phase key modulators each comprise quadrature phase shift keying modulators. 
     
     
       8. A high power transmitter comprising: a high power RF carrier source for generating a high power RF carrier signal;   a 90° hybrid for splitting the carrier signal along two paths;   two seven way power splitters coupled to the 90° hybrid and respectively disposed along the two paths that separately distribute the split carrier signal;   a lookup table containing 64 words by 14 bits for receiving 6-tuple transmit data that is to be transmitted and mapping data that maps the transmit data to the stored words in the lookup table, for generating 14-tuple modulating data;   a plurality of sets of bi-phase modulators respectively coupled to each of the outputs of the power splitters and to the lookup table for phase key modulating each of the signal components of the split carrier signal using the 14-tuple modulating data supplied by the lookup table; and   two seven way power combiners coupled to outputs of the respective sets of modulators that combine the outputs of the respective sets of modulators; and   a 0° hybrid coupled to the seven way power combiners for combining the respective outputs thereof to produce a 64 QAM constellation that is output from the transmitter.